Rethinking burning in Sisters' forests

The Deschutes National Forest is currently engaged in prescribed burning and thinning the forest.

They assert that our forests are unhealthy and too dense, thus requiring human ignition and logging to keep the forests healthy.

At the same time it promotes chainsaw medicine and human manipulation, it conveniently asserts that natural evolutionary sources of mortality like disease, wildfire, drought, and insects are “signs” that the forests are unhealthy. 

There are a couple of observations that one should consider.

1. Ponderosa pine has existed as a species for 55 million years. Humans have only been in North America for perhaps 15,000 years or so. One must ask how did ponderosa pine survive all those millions of years before humans were here to “manage” the forest? Gosh, before humans arrived, these forests must have been an ecological mess. 

2. While ponderosa pine has adaptations to survive low-severity fire, like a thick bark, self-pruning, and other adaptations, it is one of the few species adapted to low severity-high frequency fire and even among ponderosa pine the occasional mixed to high severity is a natural event. 

By contrast, nearly all plant communities in the West including sagebrush, juniper, fir, spruce, aspen, and numerous others typically experience long fire-free intervals of many decades to hundreds of years. And when they burn, they tend to experience high-severity blazes where a good percentage of plants and trees are killed.

3. Assertions that thinning and prescribed burns will preclude large fires is delusional. Large high-severity fires are climate/weather-driven events. Under such conditions, thinning/logging and prescribed burns have little influence on the fire spread. All high-severity blazes are driven by high winds, typically under drought conditions. . 

Under such conditions, high winds transport embers a mile or two ahead of the main firefront, starting new blazes. This means the fires jump over and around “fuel treatments. “It also limits helicopters and air tankers. And no fire boss will put his crew in front of a wind-driven blaze.

Such wildfires do not come under “control” until nature changes the conditions that promote such blazes, like strong wind and high temperatures.

Witness the Holiday Farm Fire along the McKenzie River that burned through miles of industrial clear-cuts. If clear-cuts won’t stop a wind-driven blaze, suggesting some forest thinning/logging or even a prescribed burn will stop a fire is delusional.

4. Natural processes like wildfire, drought, insects, and other sources of mortality remove trees that are not adapted to current climatic conditions. A logger with a paint gun marking trees for removal has no idea which trees are genetically adapted to the new environment. Therefore thinning, by randomly removing trees, degrades our forests and makes them less healthy. 

5. The solution to wind-driven blazes is to harden homes and work from the structure outward. A recent report from California found that removing burnable materials five feet from the base of the house, and fire-resistance roofs, can reduce home losses by up to 50 percent. To the degree that prescribed burn and thinning is implemented it should be located immediately around communities and buildings and must be maintained. I have seen numerous prescribed burn areas where vegetation grew back within a few years, often more vigorously than what existed before treatment. And logging the forest can open up the stand to more wind penetration and drying — both conditions that favor fire spread.

6. Of course, the ultimate cause of all of these forest issues is not fuels but climate. The human contribution of CO2 is warming the planet, and plant communities are responding and adapting to the new conditions.

George Wuerthner is an ecologist who has published several books on wildfire. He lives in Bend.